JPH0882568A - Device and method for leak detection - Google Patents

Abstract

PURPOSE: To improve leak detection accuracy by decreasing residual level of leak detection gas in a chamber. CONSTITUTION: A leak detection device 1 is provided with a chamber 2, gas supply system 3, chamber exhaust system 4, gas detector 22 and air supply system 5. In the chamber 2, a torque converter T is assigned. The chamber exhaust system 4 exhausts the content of the chamber 2. The gas detector 22 detects presence of helium in the gas of the chamber 2 exhausted by the chamber exhaust system 4. The gas supply system 3 feeds helium, of the first time, into the torque converter T in the chamber 2, and as a result, only when the gas detector 22 does not detect the helium, helium of the second time, which is more than that of the first time, is fed into the torque converter T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting device and a leak detecting method for detecting a leak of a work.

[0002]

2. Description of the Related Art Conventionally, as a method for detecting a leak of a work, there are a water immersion detection method, a differential pressure measurement method, and a specific gas detection method. A leak detection device used in a specific gas detection method includes a chamber in which a work is arranged, a leak detection gas supply device that supplies a leak detection gas to the inside of the work in the chamber, and an exhaust device that exhausts the inside of the chamber. And a leak detection gas detection device for detecting the leak detection gas from the gas in the chamber arranged by the exhaust device.

In such an apparatus, a work is first carried into the chamber. Then, the evacuation device starts evacuation of the chamber. Next, the gas supply device supplies the leak detection gas into the work. Here, the detection device checks the presence or absence of the leak detection gas from the gas in the chamber. If the leak detection gas is detected, the work is treated as a defective product.

[0004]

In the conventional leak detecting apparatus and leak detecting method described above, when the work leak is continuously detected, the leak detecting gas remains in the chamber. Further, when the work has a relatively large hole, the residual level of the leak detection gas in the chamber becomes high. If the leak detection gas remains in the chamber as described above, the accuracy of leak detection deteriorates. Therefore, conventionally, cleaning was performed by supplying clean air to the periphery of the chamber with the chamber open, but the cleaning cannot be sufficiently performed.

An object of the present invention is to improve the leak detection accuracy by lowering the residual level of the leak detection gas in the chamber.

[0006]

A leak detection device according to one aspect of the present invention is a device for supplying a leak detection gas to the inside of a work to detect a leak, and includes a chamber, an exhaust device, and a leak detection device. A gas detection device and a leak detection gas supply device are provided. A work is placed inside the chamber. The exhaust device exhausts the inside 2 of the chamber. The leak detection gas detection device checks the presence or absence of the leak detection gas from the gas in the chamber exhausted by the exhaust device.
The leak detection gas supply device supplies the first leak detection gas to the inside of the work in the chamber, and only when the detection gas detection device does not detect the leak detection gas, a larger amount than the first time is detected. The second leak detection gas is supplied into the work.

The leak detecting gas supply device includes a gas supply part, a gas supply pipe extending from the gas supply part into the chamber,
It is preferable to have a first valve and a second valve arranged in order from the chamber side in the middle of the gas supply pipe, and a valve control device. The valve control device stores the first leak detection gas in the gas supply pipe between both valves by closing the first valve and opening the second valve, and then opens the first valve to open the first leak. A detection gas is supplied into the work. The valve control device further supplies the second leak detection gas from the gas supply unit into the work by opening the second valve.

The leak detecting gas is preferably helium. A leak detection method according to another aspect of the present invention is a method for detecting a leak of a work, and includes a carry-in step, an exhaust step, a first supply step, a first detection step, a second supply step, and a second detection step. Is equipped with. In the carry-in step, the work is carried into the chamber. In the exhaust process, the inside of the chamber is exhausted after the carry-in process. In the first supply step, the first leak detection gas is supplied to the inside of the work during the exhaust step. In the first detection step, the presence or absence of the first leak detection gas is checked from the exhausted gas in the chamber. In the second supply step, a larger amount of the second leak detection gas than the first leak detection gas is supplied to the inside of the work only when the first detection step does not detect the first leak detection gas. . In the second detection step, the presence or absence of the second leak detection gas is checked from the exhausted gas in the chamber.

Both leak detecting gases are preferably helium.

[0010]

In the present invention, the work is first carried into the chamber. Then, the chamber is evacuated. During this evacuation, the first leak detection gas is supplied to the inside of the workpiece, and at the same time, the presence or absence of the first leak detection gas is checked from the exhausted gas in the chamber. Further, only when the leak detecting gas is not detected, the second leak detecting gas is supplied into the work in a larger amount than the first leak detecting gas. Then, the presence or absence of the second leak detection gas is checked.

In the above steps, it is possible to determine whether or not there is a large leak portion in the work by detecting the leak detecting gas for the first time. That is, if the first leak detecting gas is detected, there is a large leak portion in the work, and the second leak detecting gas is not supplied and detected. As a result, a large amount of leak detection gas does not leak into the chamber. As a result, even when the leak detection of the work is continuously performed, the residual level of the leak detection gas in the chamber is constantly lowered, and the leak detection accuracy is maintained high.

When the leak detecting gas supply device has a gas supply portion, a gas supply pipe, a first valve, a second valve and a valve control device, the valve control device closes the first valve and opens the first valve. By opening the two valves, the gas for leak detection for the first time is stored in the gas supply pipe between both valves, and then the first
By opening the valve, the first leak detection gas is supplied into the work. Further, the valve control device is
By opening the valve, the second leak detection gas from the gas supply unit is supplied into the work. Here, the first leak detection gas is stored between the first valve and the second valve, and therefore the structure for supplying a small amount of leak detection gas is simplified.

When the leak detecting gas is helium, the helium has a small molecule, so that the leak detecting accuracy is improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A leak detecting device 1 shown in FIG. 1 is a device for detecting a leak of a torque converter T after welding is completed. The leak detection device 1 mainly includes a chamber 2, a helium supply system 3, a chamber exhaust system 4, an air supply system 5, a drive system 6, a controller 7 (FIG. 2), and a gas detector 22.

The chamber 2 is composed of a cover plate portion 11 forming the upper surface and side surfaces of the chamber 2 and a bottom plate portion 12 forming the lower surface of the chamber 2. The bottom plate portion 12 abuts the lower portion of the cover tray portion 11 to form the chamber 2, and can be separated from the cover tray portion 11 by a drive system 6 (described later). A torque converter T is placed on the bottom plate portion 12.

The helium supply system 3 is mainly composed of a helium supply port 13, a gas supply device 14, a gas supply pipe 15, a first valve 16 and a second valve 17. The helium supply port 13 is provided in the central portion of the cover plate portion 11 and is arranged so as to be in close contact with the hydraulic pressure intake portion of the torque converter T arranged in the chamber 2. The gas supplier 14 is composed of a helium tank or the like, and is connected to the helium supply port 13 via a gas supply pipe 15. A first valve 16 and a second valve 17 are arranged in the gas supply pipe 15 in order of the helium supply port 13 side.

The chamber exhaust system 4 is mainly composed of an exhaust port 18, a vacuum pump 19, an exhaust pipe 20 and an exhaust valve 21. The exhaust port 18 is provided in the upper part of the cover plate 11. The vacuum pump 19 is connected to the exhaust port 18 via an exhaust pipe 20. In the exhaust pipe 20, an exhaust valve 21 and a gas detector 22 are arranged in order from the exhaust port 18 side. The gas detector 22 is a device capable of detecting helium in the gas exhausted by the vacuum pump 19.

The air supply system 5 is mainly composed of an air supply port 25, an air supply device 26, an air supply pipe 27 and an air valve 28. The air supply port 25 is formed on the side portion of the cover tray 11. The air supply device 26 is composed of, for example, an air tank filled with clean air, and is connected to the air supply port 25 via an air supply pipe 27. An air valve 28 is provided in the air supply pipe 27.

The drive system 6 will be described. A support portion 31 is provided below the bottom plate portion 12. The drive unit 32 is connected to the support unit 31. The bottom plate portion 12 can be moved up and down and moved laterally by the drive portion 32.
The control unit 7 shown in FIG. 2 is, for example, a CPU, RAM, ROM
2 is a control device including a microcomputer including a storage device such as a gas supply device, a first gas supply device, and a first gas supply device.
The valve 16, the second valve 17, the exhaust valve 21, the gas detector 22, the vacuum pump 19, the air supplier 26, the air valve 28, the drive unit 32, and other input / output devices are connected.

Using the control flow chart shown in FIG. 3,
The control operation of the control unit 7 will be described. In step S1, the entire device is initialized. Specifically, the first valve 1
6. The exhaust valve 21 and the air valve 28 are closed, and the second valve 17 is opened. Also, the contents of the storage device composed of RAM are initialized. Further, the gas supplier 14, the vacuum pump 19 and the air supplier 26 are activated. In step S2, the drive unit 32 is driven to carry the torque converter T placed on the bottom plate 12 into the chamber 2. Here, the inside of the torque converter T is evacuated using the vacuum pump 19.

In step S3, the exhaust valve 21 is opened to start the vacuum exhaust of the chamber 2. In step S4, the air valve 28 is opened for a certain period of time and then closed. During this time, clean air is supplied from the air supplier 26 into the sealed chamber 2. Therefore, the helium remaining in the chamber 2 is quickly exhausted, and the residual level of helium in the chamber 2 is lowered.

In step S5, the second valve 17 is closed,
In step S6, the first valve 16 is opened. As a result, the gas supply pipe 15 between the first valve 16 and the second valve 17
Helium accumulated in the torque converter T is supplied from the helium supply port 13 into the torque converter T. Here, since the inside of the torque converter T is evacuated in advance, mixing of helium and air is unlikely to occur.

In step S7, the gas detector 22 is operated to check whether or not helium is present in the chamber 2. At this time, since the amount of helium supplied to the torque converter T is small, helium leaks into the chamber 2 and is detected by the gas detector 22 only when the torque converter T has a large leak location. In this step, the presence or absence of helium is stored. If helium is not detected, the process proceeds to step S8, and if helium is detected, the process proceeds to step S10.

In step S8, the second valve 17 is opened. Then, a large amount of helium from the gas supplier 14 is supplied into the torque converter T. In step S9,
The gas detector 22 is activated again to check for the presence of helium. Since the pressure acting on the torque converter T at this time is high, it is possible to detect even if the leak location of the torque converter T is small. Also in this step, the presence or absence of helium is stored. In step S10, the exhaust valve 2
1 is closed and the vacuum exhaust in the chamber 2 is stopped.

When helium is not detected in step S7, the processing in steps S8 and S9 is skipped, so that a large amount of helium is not supplied to the torque converter T having a large leak point. Therefore, a large amount of helium leaks into the chamber 2 in the case of the torque converter T having a large leak point in the related art, but such a situation does not occur in this embodiment.

In step S11, the drive portion 32 is driven to move the bottom plate portion 12 downward, and the torque converter T is carried out of the chamber 2. In step S12, it is determined whether or not there is a leak in the torque converter T from the results stored in steps S7 and S9. Both steps S
If both of the stored results of 7 and S9 indicate that there is no leak, the process proceeds to step S13, where the drive unit 32 is driven to convey the torque converter T to the good product storage. If at least one of the results stored in steps S7 and S9 indicates that there is a leak, the process proceeds to step S14, the second valve 17 is opened, and the drive unit 32 is driven to drive the torque converter T in step S15. Are transported to the defective product storage area. When the conveyance is completed in step S13 or step S15, the storage device is initialized in step S16, and then the process returns to step S2 to detect the leak of the next torque converter T.

Helium is recovered from the torque converter T after the leak inspection is completed. This helium can be reused because it is not mixed with air. The air is not mixed in the torque converter T before the leak inspection.
This is because the inside was evacuated. By using helium as the leak detection gas, leak detection can be reliably performed even if the leak location in the torque converter T is small.
That is, since the molecule of helium is small, it easily leaks from the torque converter T. Moreover, since helium is small in the atmosphere, it is reliably detected.

Further, as an advantage of using helium,
Since helium is inactive, it does not adversely affect the torque converter T, the leak detection device 1, or the surrounding environment. As described above, since the residual level of helium in the chamber 2 is reduced in advance before supplying helium into the torque converter T, the detection accuracy of the gas detector 22 is increased. Further, by supplying a small amount of helium, a large leak point of the torque converter T is detected, and by not increasing the helium pressure in the torque converter T where the large leak point exists, the residual helium level in the chamber 2 is increased. To prevent. As a result, the air supply time in step S4 is shortened. Furthermore, by combining the above two effects, the accuracy of helium detection in the gas detector 22 is further improved.

[0029]

According to the present invention, it is possible to judge whether or not there is a large leak portion in the work by detecting the first leak detecting gas. That is, if the first leak detecting gas is detected, there is a large leak portion in the work, and the second leak detecting gas is not supplied and detected. As a result, a large amount of leak detection gas does not leak into the chamber. As a result, even when the leak detection of the work is continuously performed, the residual level of the leak detection gas in the chamber is constantly lowered, and the leak detection accuracy is maintained high.

When the gas supply device for leak detection has a gas supply part, a gas supply pipe, a first valve, a second valve and a valve control device, the first gas for leak detection is the first valve. It is stored between the second valve and the second valve, so that the structure for supplying a small amount of leak detection gas is simplified. When the leak detection gas is helium, the molecule of helium is small, so the leak detection accuracy is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a leak detection device as an embodiment of the present invention.

FIG. 2 is a block diagram showing a control configuration of a leak detection device.

FIG. 3 is a flowchart showing a control operation of a control unit of the leak detection device.

[Explanation of symbols]

 1 Leak Detector 2 Chamber 3 Helium Supply System 4 Chamber Exhaust System 5 Air Supply System 22 Gas Detector

Claims (5)

[Claims] 1. A leak detection device for detecting a leak of a work, comprising a chamber in which the work is disposed, an exhaust device for exhausting the inside of the chamber, and the chamber exhausted by the exhaust device. A leak detection gas detection device for checking the presence or absence of leak detection gas from the gas inside, and a first leak detection gas is supplied to the inside of the work in the chamber, and as a result, the leak detection gas detection device leaks. A leak detection device comprising: a leak detection gas supply device that supplies a second leak detection gas in a larger amount than the first time to the inside of the work only when the detection gas is not detected. 2. The leak detecting gas supply device includes a gas supply unit, a gas supply pipe extending from the gas supply unit into the chamber, and a gas supply pipe disposed in the middle of the gas supply pipe in order from the chamber side. A first valve and a second valve, and a valve control device, wherein the valve control device closes the first valve and opens the second valve so that the gas supply pipe between the valves has the first valve. The gas for leak detection for the second time is stored, and then the first valve is opened.
The gas for leak detection for the second time is supplied to the inside of the work,
The leak detection device according to claim 1, further comprising opening the second valve to supply the second leak detection gas from the gas supply unit into the work. 3. The leak detection device according to claim 1, wherein the leak detection gas is helium. 4. A leak detection method for detecting a leak of a work, comprising: a carry-in step of carrying in the work into a chamber; an exhaust step of exhausting the inside of the chamber after the carry-in step; A first supply step of supplying a first leak detection gas into the workpiece, a first detection step of checking the presence or absence of the first leak detection gas from the exhausted gas in the chamber; The second supply step of supplying a larger amount of the second leak detection gas than the first leak detection gas into the workpiece only when the first leak detection gas is not detected in the first detection step. And a second detection step of checking the presence or absence of the second leak detection gas from the exhausted gas in the chamber. 5. The leak detection method according to claim 4, wherein the both leak detection gases are helium.